Notes from video description and nuggets buried in comment replies: SCOP 2.99; "very small radiators, no cavity insulation" (but some attention to air tightness I suspect). "Vaillant Arotherm Plus. The load is about 6 kW … 22mm pipe." (He thinks the Vaillant HPs are much better than Mitsubishi, but more expensive.) "It was a pretty much consistent 21c internal temperature internally all week." "Weather compensated … curve selected is set for around 55c at -1."